validators.py 文件源码

def preserve_signature(func):
    """Preserve the original function signature and attributes in decorator wrappers."""
    from inspect import getargspec, formatargspec
    from gnutls.constants import GNUTLSConstant
    constants  = [c for c in (getargspec(func)[3] or []) if isinstance(c, GNUTLSConstant)]
    signature  = formatargspec(*getargspec(func))[1:-1]
    parameters = formatargspec(*getargspec(func), **{'formatvalue': lambda value: ""})[1:-1]
    def fix_signature(wrapper):
        if constants:
            ## import the required GNUTLSConstants used as function default arguments
            code = "from gnutls.constants import %s\n" % ', '.join(c.name for c in constants)
            exec code in locals(), locals()
        code = "def %s(%s): return wrapper(%s)\nnew_wrapper = %s\n" % (func.__name__, signature, parameters, func.__name__)
        exec code in locals(), locals()
        new_wrapper.__name__ = func.__name__
        new_wrapper.__doc__ = func.__doc__
        new_wrapper.__module__ = func.__module__
        new_wrapper.__dict__.update(func.__dict__)
        return new_wrapper
    return fix_signature

# Argument validating decorators
#